This application is the national phase under 35 U.S.C. xc2xa7371 of PCT International Application No. PCT/JP00/05168 which has an International filing date of Aug. 2, 2000, which designated the United States of America.
The present invention relates to a polymeric compound which is useful as a photoresist resin for use in, for example, the micromachining of semiconductors, and to a photoresist resin composition which contains this polymeric compound.
Positive photoresists for use in manufacturing processes of semiconductors must coincidentally have different characteristics such as a characteristic that an exposed portion is made soluble in alkali by light irradiation, adhesion to silicon wafers, plasma-etching resistance, and transparency to light used. The positive photoresist is generally used as a solution containing a base component polymer, a light-activatable acid generator, and several types of additives for controlling the above characteristics. It is very important for the base component polymer to have the above individual characteristics in balance in order to prepare an appropriate resist according to its use.
The wavelength of a light source in lithography for use in semiconductor manufacturing becomes shorter and shorter in recent years, and ArF excimer laser with a wavelength of 193 nm is promising as a next-generation light source. The use of a unit containing an alicyclic hydrocarbon skeleton has been proposed as a monomer unit for a resist polymer for use in the ArF excimer laser exposure system (e.g., Japanese Patent No. 2776273). Such an alicyclic hydrocarbon skeleton is highly transparent with respect to light with the aforementioned wavelength and is resistant to etching. The use of a polymer having an adamantane skeleton as a resist polymer is also known, which adamantane skeleton exhibits especially high etching resistance among alicyclic hydrocarbon skeletons. However, such alicyclic hydrocarbon skeletons are highly hydrophobic and have therefore low adhesion to substrates, although they have high etching resistance as mentioned above. To relieve this disadvantage, the aforementioned Japanese patent therefore proposes a copolymer containing highly hydrophilic monomer units (adhesion-imparting monomer units) having, for example, a carboxyl group or a lactone ring. However, these monomer units are not resistant to etching, and the etching resistant of the overall polymer becomes insufficient when the polymer contains a sufficient amount of the monomer units to satisfy the required adhesion.
Separately, Japanese Unexamined Patent Application Publication No. 11-109632 has a try at imparting hydrophilicity to an adamantane skeleton by introducing a hydroxyl group thereto. However, the polymer proposed in the publication uses t-butyl (meth)acrylate as a monomer unit (alkali-soluble monomer unit) which becomes soluble in alkali by action of an acid generated by light irradiation, and the etching resistance of the overall polymer is still insufficient.
Attempts have been made to use a monomer unit having an adamantane skeleton itself as an alkali-soluble monomer unit (e.g., Japanese Unexamined Patent Application Publication No. 9-73173, Japanese Unexamined Patent Application Publication No. 9-90637, Japanese Unexamined Patent Application Publication No. 10-274852, Japanese Unexamined Patent Application Publication No. 10-319595, Japanese Unexamined Patent Application Publication No. 11-12326, and Japanese Unexamined Patent Application Publication No. 11-119434). However, monomers lacking etching resistance are used as the adhesion-imparting monomer units in these polymers, and the overall resulting polymers are still insufficient in etching resistance.
Accordingly, it is an object of the present invention to provide a polymeric compound having not only satisfactory transparency, alkali-solubility, and adhesion but also high etching resistance, as well as to provide a photoresist resin composition containing the polymeric compound.
After intensive investigations, the present inventors found that, when a polymer containing a monomer unit having an adamantane skeleton with a specific structure is used as a photoresist resin, the resulting photoresist resin has satisfactory etching resistance, in addition to excellent transparency, alkali-solubility and adhesion. The present invention has been accomplished based on these findings.
Specifically, the present invention provides, in an aspect, a polymeric compound which includes at least one monomer unit selected from among the following formulae (I), (II), (III) and (IV): 
(wherein R1 is a hydrogen atom or a methyl group, R2 and R3 are the same or different and are each a hydrogen atom, a hydroxyl group or a xe2x80x94COOR4 group, where R4 is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group; R5 and R6 are the same or different and are each a hydrogen atom, a hydroxyl group or an oxo group; R7, R8 and R9 are the same or different and are each a hydrogen atom or a methyl group; R10 and R11 are the same or different and are each a hydrocarbon group having 1 to 8 carbon atoms; R12, R13 and R14 are the same or different and are each a hydrogen atom, a hydroxyl group or a methyl group, where if all of R12 to R14 are each a hydrogen atom or a hydroxyl group, R10 and R11 are not coincidentally methyl groups)
[wherein, when the polymeric compound comprises a monomer unit of Formula (II) in which R5xe2x95x90R6xe2x95x90H or comprises a monomer unit of Formula (III), the polymeric compound further comprises at least one monomer unit selected from among a monomer unit represented by Formula (I), a monomer unit of Formula (II) in which at least one of R5 and R6 is a hydroxyl group or an oxo group, a monomer unit represented by Formula (IV) and a monomer unit represented by the following Formula (V): 
(wherein R15 and R16 are the same or different and are each a hydrogen atom, a hydroxyl group or a carboxyl group; R17 is a hydroxyl group, an oxo group or a carboxyl group; and R1 has the same meaning as defined above)].
The polymeric compound may include at least one monomer unit selected from among Formulae (I), (II) and (III); and at least one monomer unit represented by Formula (V).
Alternatively, the polymeric compound may include at least one monomer unit represented by Formula (IV); and at least one monomer unit (excluding the monomer unit represented by Formula (IV)) selected from the following formulae (VI) and (II): 
(wherein R1 is a hydrogen atom or a methyl group; R18 and R19 are the same or different and are each a hydrocarbon group having 1 to 8 carbon atoms; R20 and R21 are the same or different and are each a hydrogen atom, a hydroxyl group, a carboxyl group or a xe2x80x94COOR group; R22 is a hydroxyl group, an oxo group, a carboxyl group or a xe2x80x94COOR group, where R is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group; m denotes 0 or 1; and R5 and R6 are the same or different and are each a hydrogen atom, a hydroxyl group or an oxo group).
The polymeric compound may further include at least one monomer unit selected from among a monomer unit represented by the following Formula (VII): 
(wherein R1 and R23 are the same or different and are each a hydrogen atom or a methyl group),
a monomer unit represented by the following Formula (VIII): 
(wherein R24 is a tricyclo[5.2.1.02,6]decylmethyl group, a tetracyclo[4.4.0.12,5.17,10]dodecylmethyl group, a norbornyl group, an isobornyl group or a 2-norbornylmethyl group; R is a substituent of R24 and is a hydrogen atom, a hydroxyl group, a hydroxymethyl group, a carboxyl group or a xe2x80x94COOR26 group, where R26 is a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or an 2-oxepanyl group; and R1 has the same meaning as defined above),
a monomer unit represented by the following Formula (IX): 
(wherein R27, R28, R29, R30 and R31 are the same or different and are each a hydrogen atom or a methyl group; and R1 has the same meaning as defined above),
a monomer unit represented by the following Formula (X): 
(wherein n denotes an integer of 1 to 3; and R1 has the same meaning as defined above),
and a monomer unit represented by the following Formula (XI): 
(wherein R1 has the same meaning as defined above).
In the polymeric compound, the total content of monomer units each having an adamantane skeleton may occupy, for example, 50% to 100% by weight, and preferably 70% to 100% by weight of total monomer units constituting the polymer.
The polymeric compound can be used as a photoresist resin.
The present invention provides, in another aspect, a photoresist resin composition which includes the polymeric compound and a light-activatable acid generator.
The terms xe2x80x9cacrylic (acrylyl)xe2x80x9d and xe2x80x9cmethacrylic (methacrylyl)xe2x80x9d as used in the present description may be generically referred to as xe2x80x9c(meth)acrylicxe2x80x9d or xe2x80x9c(meth) acrylylxe2x80x9d.
A polymeric compound of the present invention comprises at least one monomer unit selected from among Formulae (I), (II), (III) and (IV) as a constitutional unit. However, when the polymeric compound comprises a monomer unit of Formula (II) in which R5xe2x95x90R6xe2x95x90H or a monomer unit of Formula (III), the polymeric compound further comprises at least one monomer unit selected from among a monomer unit represented by Formula (I), a monomer unit of Formula (II) in which at least one of R5 and R6 is a hydroxyl group or an oxo group, a monomer unit represented by Formula (IV), and a monomer unit represented by Formula (V).
In Formula (II), R5 and R6 are each a group combined with a carbon atom constituting an adamantane ring. When each of these groups is a hydroxyl group, it is generally combined with the adamantane ring at a bridgehead position. In Formula (V), R17 is a group combined with a carbon atom constituting the adamantane ring. When this group is a hydroxyl group or a carboxyl group, it is generally combined with the adamantane ring at a bridgehead position.
In Formula (IV), hydrocarbons each having 1 to 8 carbon atoms in R10 and R11 include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, pentyl, isopentyl, 1-methylbutyl, 1-ethylpropyl, hexyl, isohexyl, 1-methylpentyl, 1-ethylbutyl, heptyl, 1-methylhexyl, octyl, 1-methylheptyl and other C1-C8 alkyl groups; cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and other C3-C8 cycloalkyl groups; and phenyl group. Among these groups, methyl, ethyl, isopropyl and other C1-C3 alkyl groups are preferred. In this connection, when none of R12 to R14 is a methyl group (when all of R12 to R14 are each a hydrogen atom or a hydroxyl group), R10 and R11 are not coincidentally methyl groups.
In the monomer unit represented by Formula (I), a carboxyl group, which is combined with the adamantane skeleton and is protected with a protective group, is deprotected by action of an acid to thereby form a free carboxyl group. In the monomer unit represented by Formula (II), an adamantane skeleton is eliminated from a carboxylic acid moiety combined with a principle chain by action of an acid to thereby form a free carboxyl group. Additionally, in the monomer unit represented by Formula (III), a lactone ring is eliminated from a carboxylic acid moiety combined with a principle chain by action of an acid to thereby form a free carboxyl group. Furthermore, in the monomer unit represented by Formula (IV), a moiety containing an adamantane skeleton is eliminated from a carboxylic acid moiety combined with a principle chain by action of an acid to thereby form a free carboxyl group. Accordingly, these monomer units of Formulae (I) to (IV) (hereinafter may be referred to as xe2x80x9cmonomer unit 1xe2x80x9d) act as alkali-soluble units which become soluble in developing with an alkali. In this connection, the monomer unit of Formula (III) also has an adhesive function to substrates, since it contains a hydrophilic lactone ring. Of monomer units represented by Formula (IV), a monomer unit, in which at least one (preferably two or three) of R12 to R14 is a hydroxyl group, has a high hydrophilicity and has an adhesive function.
The polymeric compounds according to the present invention have, as described above, the function of being soluble in alkali and each contain a monomer unit having an adamantane skeleton [the monomer unit of Formula (III) is used in combination with the monomer unit of Formula (I), (II), (IV) or (V)], and therefore have a feature that they are excellent in transparency and are very highly resistant to etching. Additionally, the polymeric compounds can exhibit a satisfactory adhesive function by appropriately incorporating the monomer unit of Formula (III), the monomer unit of Formula (V), a monomer unit of Formula (IV) in which at least one of R12 to R14 is a hydroxyl group, or another hydrophilic monomer unit. Accordingly, the invented polymeric compounds can be advantageously used as photoresist resins.
In a preferred embodiment of the present invention, the polymeric compound comprises at least one monomer unit selected from among Formulae (I), (II) and (III) (hereinafter may be referred to as xe2x80x9cmonomer unit 1axe2x80x9d), and at least one monomer unit represented by Formula (V) (hereinafter may be referred to as xe2x80x9cmonomer unit 2axe2x80x9d). Monomer unit 2a has a highly hydrophilic group (hydroxyl group, carboxyl group or oxo group) combined with the adamantane skeleton and therefore plays a role as a adhesion-imparting unit which improves adhesion to substrates.
The polymeric compound containing both monomer unit la and monomer unit 2a has very well-rounded individual characteristics including alkali solubility, adhesion to substrates, plasma-etching resistance and transparency.
In such a polymeric compound containing both monomer unit la and monomer unit 2a, the ratio of monomer unit 1a to monomer unit 2a is, for example, such that the former/the latter (by mole) is from about 1/99 to about 99/1, preferably from about 5/95 to about 80/20, and more preferably from about 15/85 to about 65/35.
In another preferred embodiment of the present invention, the polymeric compound comprises at least one monomer unit represented by Formula (IV) (hereinafter may be referred to as xe2x80x9cmonomer unit 1bxe2x80x9d) and at least one monomer unit selected from among Formulae (VI) and (II) (excluding the monomer unit represented by Formula (IV)) (hereinafter may be referred to as xe2x80x9cmonomer unit 2bxe2x80x9d). In this connection, monomer unit 2a and monomer unit 2b may be generically referred to as xe2x80x9cmonomer unit 2xe2x80x9d.
In Formula (VI), hydrocarbons each having 1 to 8 carbon atoms in R18 and R19 include similar hydrocarbons to those mentioned above. Among them, methyl, ethyl, isopropyl and other C1-C3 alkyl groups are preferred. R22 is a group combined with a carbon atom constituting an adamantane ring. When this group is a hydroxyl group or a carboxyl group, it is generally combined with the adamantane ring at a bridgehead position.
Monomer unit 2b has a highly hydrophilic group (hydroxyl group, carboxyl group or oxo group) combined with the adamantane ring and plays a role as adhesion-imparting unit which improves adhesion to substrates. Additionally, this unit has high etching resistance owing to its adamantane skeleton. In this connection, a monomer unit of Formula (VI) in which m is 1, a monomer unit of Formula (VI) in which R22 is a xe2x80x94COOR group, and the monomer unit of Formula (II) each form a free carboxyl group by action of an acid and also have the function of being soluble in alkali. A monomer unit of Formula (VI) in which R20 and R21 are both hydrogen atoms and R22 is a xe2x80x94COOR group, and a monomer unit of Formula (II) in which R5 and R6 are both hydrogen atoms have no adhesion function. However, these monomer units have the function of being soluble in alkali as mentioned above, and the combination use of these monomer units with a monomer unit of Formula (IV) in which at least one (preferably two or three) of R12 to R14 is a hydroxyl group allows the resulting polymeric compound to have the function of being soluble in alkali and adhesion function in balance.
A polymeric compound having both monomer unit 1b and monomer unit 2b, in which each of the two units has an adamantane skeleton, can yield high etching resistance and is very highly balanced in individual characteristics including alkali solubility, adhesion to substrates, plasma-etching resistance and transparency. In such a polymeric compound, the ratio of monomer unit 1b to monomer unit 2b is, for example, such that the former/the latter (by mole) is from about 1/99 to about 99/1, preferably from about 5/95 to about 80/20, and more preferably from about 15/85 to about 65/35.
The invented polymeric compound may further comprise at least one monomer unit (hereinafter may be referred to as xe2x80x9cmonomer unit 3xe2x80x9d) selected from among a monomer unit represented by Formula (VII) having an adamantane skeleton (having neither adhesion function nor the function of being soluble in alkali), a monomer unit represented by Formula (VIII) having a bridged alicyclic hydrocarbon skeleton other than adamantane, a monomer unit represented by Formula (IX) having a lactone skeleton, an acetal monomer unit represented by Formula (X), and a monomer unit represented by Formula (XI) having a carboxyl group, in addition to monomer unit 1, or monomer units 1 and 2.
A polymer composed of a constitutional unit having an adamantane skeleton alone is generally small in entanglement of molecules and tends to have a relatively brittle characteristic. However, this brittleness can be improved by incorporating any of the monomer units of Formulae (VIII) to (XI) into the polymer. Additionally, the monomer units of Formulae (VII) and (VIII) have high etching resistance, the monomer units of Formulae (IX) and (XI) have a adhesion-imparting function, the monomer unit of Formula (X) has the function of being soluble in alkali, and the balance of various characteristics required as a resist resin can be finely controlled according to its use by the aid of each of the aforementioned monomer units. In this connection, of the monomer units of Formula (IX), a monomer unit in which at least one of R27 to R31 is a methyl group (specifically, R30 and R31 are methyl groups) is typically preferred.
In such a polymeric compound containing monomer unit 3, the total content of monomer unit 3 occupies, for example, about 1% to 50% by mole, and preferably about 5% to 40% by mole of the total monomer units constituting the polymer.
Of the combinations of the individual monomer units in the invented polymeric compound, specifically preferred combinations are as follows:
(1) a combination of a monomer unit of Formula (I), and a monomer unit of Formula (V) in which R17 is a hydroxyl group and R15 is a hydrogen atom or a hydroxyl group;
(2) a combination of a monomer unit of Formula (I), and a monomer unit of Formula (V) in which R17 is an oxo group and R15 is a hydrogen atom or a hydroxyl group;
(3) a combination of a monomer unit of Formula (I), and a monomer unit of Formula (II) in which R5 and R6 are hydroxyl groups;
(4) a combination of a monomer unit of Formula (I) in which R2 is a hydroxyl group, and a monomer unit of Formula (III) (e.g., a monomer unit in which at least one of R7 to R9 is a methyl group, specifically a monomer unit in which R8 and R9 are methyl groups);
(5) a combination of a monomer unit of Formula (I) in which R2 is a hydroxyl group, and a monomer unit of Formula (IX) (e.g., a monomer unit in which at least one of R27 to R31 is a methyl group);
(6) a combination of a monomer unit of Formula (II) in which R5and R6 are hydrogen atoms, and a monomer unit of Formula (V) in which R17 is a hydroxyl group and R15 is a hydrogen atom or a hydroxyl group;
(7) a combination of a monomer unit of Formula (II) in which R5and R6 are hydrogen atoms, and a monomer unit of Formula (V) in which R17 is an oxo group and R15 is a hydrogen atom or a hydroxyl group;
(8) a combination of a monomer unit of Formula (II) in which R5 and R6 are hydrogen atoms, and a monomer unit of Formula (II) in which R5 and R6 are hydroxyl groups;
(9) a combination of a monomer unit of Formula (II) in which R5 is a hydroxyl group and R6 is a hydrogen atom, and a monomer unit of Formula (V);
(10) a combination of a monomer unit of Formula (II) in which R5 is a hydroxyl group and R6 is a hydrogen atom, and a monomer unit of Formula (II) in which R5 and R6 are hydroxyl groups;
(11) a combination of a monomer unit of Formula (II) in which R5 is a hydroxyl group and R6 is a hydrogen atom, and a monomer unit of Formula (III) (e.g., a monomer unit in which at least one of R7 to R9 is a methyl group, and specifically a monomer unit in which R8 and R9 are methyl groups);
(12) a combination of a monomer unit of Formula (II) in which R5 is a hydroxyl group and R6 is a hydrogen atom, and a monomer unit of Formula (IX) (e.g., a monomer unit in which at least one of R27 to R31 is a methyl group);
(13) a combination of a monomer unit of Formula (III), and a monomer unit of Formula (V) in which R17 is a hydroxyl group and R15 is a hydrogen atom or a hydroxyl group;
(14) a combination of a monomer unit of Formula (III), and a monomer unit of Formula (V) in which R17 is an oxo group and R15 is a hydrogen atom or a hydroxyl group;
(15) a combination of a monomer unit of Formula (III), and a monomer unit of Formula (II) in which R5 and R6 are hydroxyl groups;
(16) a combination of a monomer unit of Formula (I), a monomer unit of Formula (V), and a monomer unit of Formula (III);
(17) a combination of a monomer unit of Formula (I), a monomer unit of Formula (V), and a monomer unit of Formula (IX);
(18) a combination of a monomer unit of Formula (I), a monomer unit of Formula (V), and a monomer unit of Formula (X);
(19) a combination of a monomer unit of Formula (IV) in which the number of hydroxyl group combined with the adamantane ring is 0 or 1, and a monomer unit of Formula (IV) in which the number of hydroxyl group combined with the adamantane ring is 1 to 3, and specifically 2 or 3;
(20) a combination of a monomer unit of Formula (IV), and a monomer unit of Formula (VI) in which m=0;
(21) a combination of a monomer unit of Formula (IV), and a monomer unit of Formula (VI) in which m=1 and R22 is a hydroxyl group;
(22) a combination of a monomer unit of Formula (IV) in which at least one of R12 to R14 is a hydroxyl group, and a monomer unit of Formula (VI) in which m=0 and R22 is a xe2x80x94COOR group;
(23) a combination of a monomer unit of Formula (IV), and a monomer unit of Formula (II) in which at least one of R5 and R6 is a hydroxyl group (specifically, a monomer unit in which R5xe2x95x90R6xe2x95x90OH);
(24) a combination of a monomer unit of Formula (IV) in which at least one of R12 to R14 is a hydroxyl group, and a monomer unit of Formula (II);
(25) a combination of a monomer unit of Formula (IV), and a monomer unit of Formula (IX) (e.g., a monomer unit in which at least one of R27 to R31 is a methyl group);
(26) a combination of a monomer unit of Formula (IV), and a monomer unit of Formula (III) (e.g., a monomer unit in which at least one of R7 to R9 is a methyl group, specifically a monomer unit in which R8 and R9 are methyl groups);
(27) a combination of a monomer unit of Formula (IV), a monomer unit of Formula (VI) (specifically, a monomer unit in which m=0), and a monomer unit of Formula (IX);
(28) a combination of a monomer unit of Formula (IV), a monomer unit of Formula (VI) (specifically, a monomer unit in which m=0), and a monomer unit of Formula (III); and
(29) a combination of a monomer unit of Formula (IV), a monomer unit of Formula (VI) (specifically, a monomer unit in which m=0), and a monomer unit of Formula (X).
In the invented polymeric compound, the total content of monomer units each having an adamantane skeleton (Formulae (I), (II), (IV), (V), (VI) and (VII), specifically, Formulae (I), (II), (IV), (V) and (VI)) occupies, for example, about 50% to 100% by weight, and preferably about 70% to 100% by weight of the total monomer units constituting the polymer. Such polymeric compounds exhibit specifically satisfactory etching resistance.
In the present invention, the polymeric compound has a weight average molecular weight (Mw) of, for example, from about 5000 to about 50000, and preferably from about 7000 to about 20000, and a molecular weight distribution (Mw/Mn) of, for example, from about 1.8 to about 3.0. In this connection, the aforementioned Mn means a number average molecular weight (in terms of polystyrene).
Each of the monomer units represented by Formulae (I) to (XI) can be prepared by subjecting an individual corresponding (meth)acrylic ester as a (co-)monomer to polymerization. The polymerization operation can be performed by a conventional technique, such as solution polymerization or melt polymerization, for use in the production of an acrylic polymer.
[Monomer Unit of Formula (I)]
Monomers corresponding to the monomer units of Formula (I) are represented by the following Formula (1): 
(wherein R1, R2, R3 and R4 have the same meanings as defined above),
of which typical examples are the following compounds:
[1-1] 1-t-butoxycarbonyl-3-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R2xe2x95x90R3xe2x95x90H, R4=t-butyl group);
[1-2] 1,3-bis(t-butoxycarbonyl)-5-(meth)acryloyloxyadamantane [R1xe2x95x90H or CH3, R2=t-butoxycarbonyl group, R3xe2x95x90H, R4=t-butyl group];
[1-3] 1-t-butoxycarbonyl-3-hydroxy-5-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R2xe2x95x90OH, R3xe2x95x90H, R4=t-butyl group);
[1-4] 1-(2-tetrahydropyranyloxycarbonyl)-3-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R2xe2x95x90R3xe2x95x90H, R4=2-tetrahydropyranyl group);
[1-5] 1,3-bis(2-tetrahydropyranyloxycarbonyl)-5-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R2=2-tetrahydropyranyloxycarbonyl group, R3xe2x95x90H, R4=2-tetrahydropyranyl group); and
[1-6] 1-hydroxy-3-(2-tetrahydropyranyloxycarbonyl)-5-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R2xe2x95x90OH, R3xe2x95x90H, R4=2-tetrahydropyranyl group).
The compounds represented by Formula (1) can be obtained, for example, pursuantly to the following reaction process chart: 
(wherein Rx is a halogen atom, a hydroxyl group, an alkoxy group or an alkenyloxy group; and R1, R2, R3 and R4 have the same meanings as defined above).
In the reaction process chart, carboxyadamantanol derivative (12) can be converted (protection of a carboxyl group) into 1-adamantanol derivative (13) by a conventional process such as a process in which carboxyadamantanol derivative (12) is allowed to react with, for example, isobutylene, dihydrofuran or dihydropyran.
In this procedure, carboxyadamantanol derivative (12) for use as a raw material can be obtained by introducing a hydroxyl group and a carboxyl group on the adamantane ring of an adamantane compound. For example, a hydroxyl group can be introduced into the adamantane ring by a process in which the adamantane compound is brought into contact with oxygen in the presence of a N-hydroxyimide catalyst such as N-hydroxyphthalimide, and where necessary a metallic promoter (co-catalyst) such as a cobalt compound (e.g., cobalt acetate or acetylacetonatocobalt). In this process, the amount of the N-hydroxyimide catalyst is, for example, from about 0.0001 to about 1 mole, and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the adamantane compound. The amount of metallic promoter is, for example, from about 0.0001 to about 0.7 mole, and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the adamantane compound. Oxygen is often used in excess to the adamantane compound. A reaction is performed, for example, in a solvent at a temperature of from about 0xc2x0 C. to about 200xc2x0 C., and preferably from about 30xc2x0 C. to about 150xc2x0 C. at atmospheric pressure or under a pressure (under a load). Such solvents include, for example, acetic acid and other organic acids, acetonitrile and other nitrites, and dichloroethane and other halogenated hydrocarbons. A plurality of hydroxyl groups can be introduced into the adamantane ring by appropriately selecting reaction conditions.
Separately, a carboxyl group can be introduced into the adamantane ring of the adamantane compound by a process in which the adamantane compound is brought into contact with carbon monoxide and oxygen in the presence of the N-hydroxyimide catalyst, and where necessary, the metallic promoter. In the carboxylation reaction, the amount of the N-hydroxyimide catalyst is, for example, from about 0.0001 to about 1 mole, and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the adamantane compound. The amount of the metallic promoter is, for example, from about 0.0001 to 0.7 mole, and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the adamantane compound. The amounts of carbon monoxide and oxygen are, for example, 1 mole or more and 0.5 mole or more, respectively, relative to 1 mole of the adamantane compound. The ratio of carbon monoxide to oxygen is, for example, such that the former/the latter (by mole) is from about 1/99 to about 99/1, and preferably from about 50/50 to about 95/5. The carboxylation reaction is performed, for example, in a solvent at a temperature of from about 0xc2x0 C. to about 200xc2x0 C., and preferably from about 10xc2x0 C. to about 150xc2x0 C. at atmospheric pressure or under a pressure (under a load). Such solvents include, for example, acetic acid and other organic acids, acetonitrile and other nitriles, and dichloroethane and other halogenated hydrocarbons. A plurality of carboxyl groups can be introduced into the adamantane ring by appropriately selecting reaction conditions.
The reaction (esterification reaction) between 1-adamantanol derivative (13) and (meth)acrylic acid or its derivative (14) can be performed by a conventional process using an acid catalyst or a transesterification catalyst. A compound represented by Formula (1) can be efficiently obtained under mild conditions by subjecting 1-adamantanol derivative (13) to a reaction (a transesterification reaction) with an alkenyl (meth)acrylate such as vinyl (meth)acrylate or 2-propenyl (meth)acrylate in the presence of a catalyst of the compound of Group 3 element of the Periodic Table of Elements (e.g., samarium acetate, samarium trifluoromethanesulfonate, samarium complexes, and other samarium compounds). In this case, the amount of the alkenyl (meth) acrylate is, for example, from about 0.8 to about 5 moles and preferably from about 1 to about 1.5 moles, relative to 1 mole of 1-adamantanol derivative (13). The amount of the catalyst of the compound of Group 3 elements of the Periodic Table of Elements is, for example, from about 0.001 to about 1 mole and preferably from about 0.01 to about 0.25 mole, relative to 1 mole of 1-adamantanol derivative (13). This reaction is performed in a solvent inert toward the reaction at a temperature of, for example, from about 0xc2x0 C. to about 150xc2x0 C. and preferably from about 25xc2x0 C. to about 120xc2x0 C.
[Monomer Unit of Formula (II)]
Monomers corresponding to the monomer units of Formula (II) are represented by the following Formula (2): 
(wherein R1, R5 and R6 have the same meanings as defined above), of which typical examples are the following compounds:
[2-1] 2-(meth)acryloyloxy-2-methyladamantane (R1xe2x95x90H or CH3, R5xe2x95x90R6xe2x95x90H);
[2-2] 1-hydroxy-2-(meth)acryloyloxy-2-methyladamantane (R1xe2x95x90H or CH3, R5=1-OH, R6xe2x95x90H);
[2-3] 5-hydroxy-2-(meth)acryloyloxy-2-methyladamantane (R1xe2x95x90H or CH3, R5=5-OH, R6xe2x95x90H);
[2-4] 1,3-dihydroxy-2-(meth)acryloyloxy-2-methyladamantane (R1xe2x95x90H or CH3, R5=1-OH, R6=3-OH);
[2-5] 1,5-dihydroxy-2-(meth)acryloyloxy-2-methyladamantane (R1xe2x95x90H or CH3, R5=1-OH, R6=5-OH); and
[2-6] 1,3-dihydroxy-6-(meth)acryloyloxy-6-methyladamantane (R1xe2x95x90H or CH3, R5=1-OH, R6=3-OH).
The compounds represented by Formula (2) can be obtained, for example, pursuantly to the following reaction process chart: 
(wherein X is a halogen atom; and R1, R5, R6 and Rx have the same meanings as defined above).
In this reaction process chart, a reaction between adamantanone derivative (15) and Grignard reagent (16) can be performed pursuantly to a conventional Grignard reaction. The amount of Grignard reagent (16) is, forexample, from about 0.7 to about 3 moles and preferably from about 0.9 to about 1.5 moles, relative to 1 mole of adamantanone derivative (15). When adamantanone derivative (15) has hydroxyl group(s) on the adamantane ring, the amount of the Grignard reagent is increased depending on the number thereof. The reaction is performed in a solvent inert toward the reaction, such as diethyl ether, tetrahydrofuran, and other ethers. A reaction temperature is, for example, from about 0xc2x0 C. to about 150xc2x0 C. and preferably from about 20xc2x0 C. to about 100xc2x0 C.
Thus obtained 2-adamantanol derivative (17) is subjected to a reaction (an esterification reaction) with (meth)acrylic acid or its derivative (14) to thereby yield a compound represented by Formula (2). The esterification reaction can be performed pursuantly to the reaction between the compound of Formula (13) and (meth) acrylic acid or its derivative (14).
Of adamantanone derivatives (15) for use as a raw material in the above process, a compound having a hydroxyl group on the adamantane ring can be produced by a process, in which 2-adamantanone is brought into contact with oxygen in the presence of a N-hydroxyimide catalyst such as N-hydroxyphthalimide, and where necessary, a metallic promoter such as a cobalt compound, a manganese compound or a vanadium compound to thereby introduce a hydroxyl group into the adamantane ring. In this process, the amount of the N-hydroxyimide catalyst is, for example, from about 0.0001 to about 1 mole and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the 2-adamantanone. The amount of the metallic promoter is, for example, from about 0.0001 to about 0.7 mole and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the 2-adamantanone. Oxygen is often used in excess to the 2-adamantanone. The reaction is performed in a solvent at a temperature of from about 0xc2x0 C. to about 200xc2x0 C. and preferably from about 30xc2x0 C. to about 150xc2x0 C. at atmospheric pressure or under a pressure (under a load). Such solvents include, for example, acetic acid and other organic acids, acetonitrile and other nitrites, and dichloroethane and other halogenated hydrocarbons.
Of adamantanone derivatives (15), a compound having a hydroxyl group on the adamantane ring can also be produced by allowing an adamantane to react with oxygen in the presence of the N-hydroxyimide catalyst and a strong acid (e.g., a hydrogen halide or sulfuric acid), and where necessary, the metallic promoter. The amount of the strong acid is, for example, from about 0.00001 to about 1 mole and preferably from about 0.0005 to about 0.7 mole, relative to 1 mole of the adamantane. The other reaction conditions are similar to those in the reaction for the introduction of hydroxyl group.
[Monomer Unit of Formula (III)]
Monomers corresponding to the monomer units of Formula (III) are represented by the following Formula (3): 
(wherein R1, R7, R8 and R9 have the same meanings as defined above),
of which typical examples are the following compounds:
[3-1] 3-(meth)acryloyloxy-xcex3-butyrolactone (R1xe2x95x90H or CH3, R7xe2x95x90R8xe2x95x90R9xe2x95x90H);
[3-2] 3-(meth)acryloyloxy-3-methyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R7xe2x95x90CH3, R8xe2x95x90R9xe2x95x90H);
[3-3] 3-(meth)acryloyloxy-4-methyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R7xe2x95x90R9xe2x95x90H, R8xe2x95x90CH3);
[3-4] 3-(meth)acryloyloxy-3,4-dimethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R7xe2x95x90R8xe2x95x90CH3, R9xe2x95x90H);
[3-5] 3-(meth)acryloyloxy-4,4-dimethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R7xe2x95x90H, R8xe2x95x90R9xe2x95x90CH3); and
[3-6] 3-(meth)acryloyloxy-3,4,4-trimethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R7xe2x95x90R8xe2x95x90R9xe2x95x90CH3).
The compounds represented by Formula (3) can be obtained, for example, pursuantly to the following reaction process chart: 
(wherein R1, R7, R8, R9 and Rx have the same meanings as defined above).
In the above reaction process chart, conversion (isomerization) of an xcex1-hydroxy-xcex3-butyrolactone represented by Formula (18) into a xcex2-hydroxy-xcex3-butyrolactone represented by Formula (19) can be performed by dissolving the compound of Formula (18) in water or a solvent, where necessary, with small amounts of an acid such as sulfuric acid or hydrochloric acid. The solvent is not specifically limited, and includes, for example, acetonitrile, acetic acid or ethyl acetate. A reaction temperature is, for example, from about 0xc2x0 C. to about 150xc2x0 C. and preferably from about 20xc2x0 C. to about 100xc2x0 C. xcex1-Hydroxy-xcex3-butyrolactone (18) for use as a raw material can be produced in the same manner as a compound represented by Formula (32) mentioned below. The compound of Formula (19) can also be obtained by subjecting the compound of Formula (18) to a reaction (a dehydration reaction) with phosphorus pentoxide to yield a corresponding xcex1,xcex2-unsaturated-xcex3-butyrolactone, allowing this compound to react with a peracid such as hydrogen peroxide or m-chloroperbenzoic acid to epoxidize a double bond, and hydrogenating the same in the presence of a catalyst such as Pdxe2x80x94C. Alternatively, the compound of Formula (19) can also be produced by a conventional process for the preparation of a xcex2-hydroxy-xcex3-butyrolactone.
A reaction between xcex2-hydroxy-xcex3-butyrolactone (19) and the (meth)acrylic acid or its derivative represented by Formula (14) can be performed pursuantly to the reaction between the compound of Formula (13) and (meth)acrylic acid or its derivative (14).
[Monomer Unit of Formula (IV)]
Monomers corresponding to the monomer units of Formula (IV) are represented by the following Formula (4): 
(wherein R1, R10, R11, R12, R13 and R14 have the same meanings as defined above),
of which typical examples are the following compounds:
[4-1] 1-(1-ethyl-1-(meth)acryloyloxypropyl)adamantane (R1xe2x95x90H or CH3, R10xe2x95x90R11=ethyl group, R12xe2x95x90R13xe2x95x90R14xe2x95x90H);
[4-2] 1-(1-ethyl-1-(meth)acryloyloxypropyl)-3-hydroxyadamantane (R1xe2x95x90H or CH3, R10xe2x95x90R11=ethyl group, R12=OH R13xe2x95x90R14xe2x95x90H);
[4-3] 1-(1-(meth)acryloyloxy-1-methylpropyl)adamantane (R1xe2x95x90H or CH3, R10xe2x95x90CH3, R11=ethyl group, R12xe2x95x90R13xe2x95x90R14xe2x95x90H);
[4-4] 1(1-(meth)acryloyloxy-1-methylpropyl)-3-hydroxyadamantane (R1xe2x95x90H or CH3, R10xe2x95x90CH3, R11=ethyl group, R12xe2x95x90OH, R13xe2x95x90R14xe2x95x90H);
[4-5] 1-(1-(meth)acryloyloxy-1,2-dimethylpropyl)adamantane (R1xe2x95x90H or CH3, R10xe2x95x90CH3, R11=isopropyl group, R12xe2x95x90R13xe2x95x90R14xe2x95x90H);
[4-6] 1-(1-(meth)acryloyloxy-1,2-dimethylpropyl)-3-hydroxyadamantane (R1xe2x95x90H or CH3, R10xe2x95x90CH3, R11=isopropyl group, R12xe2x95x90OH, R13xe2x95x90R14xe2x95x90H);
[4-7] 1-(1-ethyl-1-(meth)acryloyloxypropyl)-3,5-dihydroxyadamantane (R1xe2x95x90H or CH3, R10xe2x95x90R11=ethyl group, R12xe2x95x90R13xe2x95x90OH, R14xe2x95x90H);
[4-8] 1,3-dihydroxy-5-(1-(meth)acryloyloxy-1-methylpropyl)adamantane (R1xe2x95x90H or CH3, R10xe2x95x90CH3, R11=ethyl group, R2xe2x95x90R13xe2x95x90OH, R4xe2x95x90H); and
[4-9] 1,3-dihydroxy-5-(1-(meth)acryloyloxy-1,2-dimethylpropyl)adamantane (R1xe2x95x90H or CH3, R10xe2x95x90CH3, R11=isopropyl group, R12xe2x95x90R13xe2x95x90OH, R14xe2x95x90H).
The compounds represented by Formula (4) can be obtained, for example, pursuant to the following reaction process chart: 
(wherein X, R1, R10, R11, R12, R13, R14 and Rx have the same meanings as defined above).
Of adamantane derivatives (20) for use as a raw material in this reaction process chart, a compound in which any of R12 to R14 is a hydroxyl group can be obtained by introducing a hydroxyl group into an adamantane ring. For example, a hydroxyl group can be introduced into the adamantane ring by a process in which an adamantane compound is brought into contact with oxygen in the presence of a N-hydroxyimide catalyst such as N-hydroxyphthalimide and, where necessary, a metallic promoter (co-catalyst) such as a cobalt compound (e.g., cobalt acetate or acetylacetonatocobalt). In this process, the amount of the N-hydroxyimide catalyst is, for example, from about 0.0001 to about 1 mole and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the adamantane compound. The amount of the metallic promoter is, for example, from about 0.0001 to about 0.7 mole and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the adamantane compound. Oxygen is often used in excess to the adamantane compound. A reaction is performed, for example, in a solvent at a temperature of from about 0xc2x0 C. to about 200xc2x0 C., and preferably from about 30xc2x0 C. to about 150xc2x0 C. at atmospheric pressure or under a pressure (under a load). Such solvents include, for example, acetic acid and other organic acids, acetonitrile and other nitrites, and dichloroethane and other halogenated hydrocarbons. A plurality of hydroxyl groups can be introduced into the adamantane ring by appropriately selecting reaction conditions.
A reaction of adamantane derivative (20) with 1,2-dicarbonyl compound (e.g., biacetyl) (21) and oxygen can be performed in the presence of a metallic compound such as a cobalt compound (e.g., cobalt acetate or acetylacetonatocobalt) and/or a N-hydroxyimide catalyst such as N-hydroxyphthalimide. The amount of 1,2-dicarbonyl compound (21) is 1 mole or more (e.g., from about 1 to about 50 moles), preferably from about 1.5 to about 20 moles and more preferably from about 3 to about 10 moles, relative to 1 mole of adamantane derivative (20). The amount of the metallic compound is, for example, from about 0.0001 to about 0.1 mole, relative to 1 mole of adamantane derivative (20). The amount of the N-hydroxyimide catalyst is, for example, from about 0.001 to about 0.7 mole, relative to 1 mole of adamantane derivative (20). Oxygen is often used in excess to adamantane derivative (20). The reaction is generally performed in an organic solvent. Such organic solvents include, but are not limited to, acetic acid and other organic acids, benzonitrile and other nitrites, and trifluoromethylbenzene and other halogenated hydrocarbons. The reaction is performed at a temperature of, for example, from about 30xc2x0 C. to about 250xc2x0 C. and preferably from about 40xc2x0 C. to about 200xc2x0 C. at atmospheric pressure or under a pressure (under a load).
A reaction between acyladamantane derivative (22) thus obtained and Grignard reagent (23) can be performed pursuantly to a conventional Grignard reaction. The amount of Grignard reagent (23) is, for example, from about 0.7 to about 3 moles and preferably from about 0.9 to about 1.5 moles, relative to 1 mole of acyladamantane derivative (22). When acyladamantane derivative (22) has hydroxyl group(s) on the adamantane ring, the amount of the Grignard reagent is increased depending on the number thereof. The reaction is performed in, for example, an ether such as diethyl ether or tetrahydrofuran. A reaction temperature is, for example, from about 0xc2x0 C. to about 150xc2x0 C. and preferably from about 20xc2x0 C. to about 100xc2x0 C.
A reaction (an esterification reaction) between adamantanemethanol derivative (24) formed by the above reaction and (meth) acrylic acid or its derivative (14) can be performed pursuantly to the reaction between the compound of Formula (13) and (meth)acrylic acid or its derivative (14).
Of the compounds represented by Formula (4), a compound in which R10 and R11 are the same groups can be obtained, for example, pursuantly to the following reaction process chart: 
(wherein Ry is a hydrocarbon group; and X, R1, R11, R12, R13, R14 and Rx have the same meanings as defined above).
The hydrocarbon group in Ry includes, but is not limited to, methyl, ethyl, propyl, isopropyl and other C1-C6 aliphatic hydrocarbon groups; and phenyl group.
Adamantanecarboxylic acid derivative (25) for use as a raw material in the above reaction process chart can be produced by introducing a carboxyl group into the adamantane ring of an adamantane compound. For example, a carboxyl group can be introduced into the adamantane ring of the adamantane compound by a process in which the adamantane compound is brought into contact with carbon monoxide and oxygen in the presence of a N-hydroxyimide catalyst such as N-hydroxyphthalimide and, where necessary, a metallic promoter (co-catalyst) such as a cobalt compound (e.g., cobalt acetate or acetylacetonatocobalt). In the carboxylation reaction, the amount of the N-hydroxyimide catalyst is, for example, from about0.0001 to about 1 mole, and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the adamantane compound. The amount of the metallic promoter is, for example, from about 0.0001 to about 0.7 mole, and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the adamantane compound. The amounts of carbon monoxide and oxygen are, for example, 1 mole or more and 0.5 mole or more, respectively, relative to 1 mole of the adamantane compound. The ratio of carbon monoxide to oxygen is, for example, such that the former/the latter (by mole) is from about 1/99 to about 99/1, and preferably from about 50/50 to about 95/5. The carboxylation reaction is performed, for example, in a solvent at a temperature of from about 0xc2x0 C. to about 200xc2x0 C., and preferably from about 10xc2x0 C. to about 150xc2x0 C. at atmospheric pressure or under a pressure (under a load). Such solvents include, for example, acetic acid and other organic acids, acetonitrile and other nitrites, and dichloroethane and other halogenated hydrocarbons. In this connection, a plurality of carboxyl groups can be introduced into the adamantane ring by appropriately selecting reaction conditions.
A reaction between adamantanecarboxylic acid derivative (25) and hydroxy compound (26) can be performed, for example, pursuantly to a conventional esterification process using an acid catalyst.
A reaction between an adamantanecarboxylic ester represented by Formula (27) and Grignard reagent (23) is generally performed in a solvent inert toward the reaction, such as diethyl ether, tetrahydrofuran and other ethers. A reaction temperature is, for example, from about 0xc2x0 C. to about 100xc2x0 C. and preferably from about 10xc2x0 C. to about 40xc2x0 C. The amount of Grignard reagent (23) is, for example, about 2 to 4 equivalents relative to adamantanecarboxylic ester (27).
A reaction (an esterification reaction) between adamantanemethanol derivative (24a) and (meth)acrylic acid or its derivative (14) can be performed pursuantly to the reaction between the compound represented by Formula (13) and (meth)acrylic acid or its derivative (14). Thus, of the compounds represented by Formula (4), a compound in which R10 and R11 are the same hydrocarbon group (e.g., R11xe2x95x90R11=ethyl group) can be easily prepared.
[Monomer Unit of Formula (V)]
Monomers corresponding to the monomer units of Formula (V) are represented by the following Formula (5): 
(wherein R1, R15, R16 and R17 have the same meanings as defined above),
of which typical examples include the following compounds: [5-1] 1-hydroxy-3-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R17xe2x95x90OH, R15xe2x95x90R 16xe2x95x90H);
[5-2] 1,3-dihydroxy-5-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R17xe2x95x90R15xe2x95x90OH, R16xe2x95x90H);
[5-3] 1-carboxy-3-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R17xe2x95x90COOH, R15xe2x95x90R16xe2x95x90H);
[5-4] 1,3-dicarboxy-5-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R17xe2x95x90R15=COOH, R16xe2x95x90H);
[5-5] 1-carboxy-3-hydroxy-5-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R17xe2x95x90OH, R15xe2x95x90COOH, R16xe2x95x90H);
[5-6] 1-(meth)acryloyloxy-4-oxoadamantane (R1xe2x95x90H or CH3, R17=4-oxo group, R15xe2x95x90R16xe2x95x90H);
[5-7] 3-hydroxy-1-(meth)acryloyloxy-4-oxoadamantane (R1xe2x95x90H or CH3, R17=4-oxo group, R15=3-OH, R16xe2x95x90H); and
[5-8] 7-hydroxy-1-(meth)acryloyloxy-4-oxoadamantane (R1xe2x95x90H or CH3, R17=4-oxo group, R15=7-OH, R16xe2x95x90H).
The compounds represented by Formula (5) can be obtained, for example, pursuantly to the following reaction process chart: 
(wherein R1, R15, R16, R17 and Rx have the same meanings as defined above).
In this reaction process chart, a reaction between 1-adamantanol derivative (28) and (meth)acrylic acid or its derivative (14) is performed pursuantly to the reaction between 1-adamantanol derivative (13) and (meth)acrylic acid or its derivative (14). By introducing a hydroxyl group or a carboxyl group into the adamantane ring of an adamantane compound, 1-adamantanol derivative (28) for use as a raw material can be obtained. The introduction of a hydroxyl group and carboxyl group into the adamantane ring can be performed in the same manner as above.
[Monomer Unit of Formula (VI)]
Monomers corresponding to the monomer units of Formula (VI) are represented by the following Formula (6): 
(wherein R1, R18, R19, R20, R21, R22 and m have the same meanings as defined above),
of which typical examples are the following compounds. In this connection, part of compounds represented by Formula (6) in which m=0 overlaps the compounds represented by Formula (5).
[6-1] 1-hydroxy-3-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90R21xe2x95x90H, R22xe2x95x90OH);
[6-2] 1,3-dihydroxy-5-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90R22xe2x95x90OH, R21xe2x95x90H);
[6-3] 1-carboxy-3-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90R21xe2x95x90H, R22xe2x95x90COOH);
[6-4] 1,3-dicarboxy-5-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90R22xe2x95x90COOH, R21xe2x95x90H);
[6-5] 1-carboxy-3-hydroxy-5-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90COOH, R21xe2x95x90H, R22xe2x95x90OH);
[6-6] 1-(meth)acryloyloxy-4-oxoadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90R21xe2x95x90H, R22=4-oxo group);
[6-7] 3-hydroxy-1-(meth)acryloyloxy-4-oxoadamantane (m=0, R1xe2x95x90H or CH3, R20=3-OH, R21xe2x95x90H, R22=4-oxo group);
[6-8] 7-hydroxy-1-(meth)acryloyloxy-4-oxoadamantane (m=0, R1xe2x95x90H or CH3, R20=7-OH, R21xe2x95x90H, R22=4-oxo group)
[6-9] 1,3-dihydroxy-5-(1-(meth)acryloyloxy-1-methylethyl)adamantane (m=1, R1xe2x95x90H or CH3, R18xe2x95x90R19xe2x95x90CH3, R20xe2x95x90R22xe2x95x90OH, R21xe2x95x90H);
[6-10] 1-t-butoxycarbonyl-3-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90R21xe2x95x90H, R22=t-butoxycarbonyl group);
[6-11] 1,3-bis(t-butoxycarbonyl)-5-(meth)acryloyloxyadamantane [m=0, R1xe2x95x90H or CH3, R20xe2x95x90R22=t-butoxycarbonyl group, R21xe2x95x90H);
[6-12] 1-t-butoxycarbonyl-3-hydroxy-5-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90OH, R21xe2x95x90H, R22=t-butoxycarbonyl group);
[6-13] 1-(2-tetrahydropyranyloxycarbonyl)-3-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90R21xe2x95x90H, R22=2-tetrahydropyranyloxycarbonyl group);
[6-14] 1,3-bis(2-tetrahydropyranyloxycarbonyl)-5-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90R22=2-tetrahydropyranyloxycarbonyl group, R21xe2x95x90H); and
[6-15] 1-hydroxy-3-(2-tetrahydropyranyloxycarbonyl)-5-(meth)acryloyloxyadamantane (m=0, R1xe2x95x90H or CH3, R20xe2x95x90OH, R21xe2x95x90H, R22=2-tetrahydropyranyloxycarbonyl group).
The compound represented by Formula (6) can be obtained, for example, pursuantly to the following reaction process chart: 
(wherein R1, R18, R19, R20, R21, R22, Rx and m have the same meanings as defined above).
Of the compounds represented by Formula (29) for use as a raw material in the reaction process chart, a compound in which m=1 can be prepared in the same manner as compound (24) or (24a). Separately, of the compounds represented by Formula (29) for use as a raw material, a compound in which m=0 can be obtained by introducing a hydroxyl group or a carboxyl group into the adamantane ring of an adamantane compound. As the introduction process of hydroxyl group or carboxyl group into the adamantane ring, the aforementioned process can be employed. Of the compounds represented by Formula (29), a compound in which R22 is a xe2x80x94COOR group can be produced by subjecting a corresponding carboxylic acid and an alcohol ROH to a conventional esterification reaction.
A reaction (an esterification reaction) between compound (29) and (meth)acrylic acid or its derivative (14) can be performed pursuantly to the reaction between the compound represented by Formula (13) and (meth)acrylic acid or its derivative (14).
[Monomer Unit of Formula (VII)] 
(wherein R1 and R23 have the same meanings as defined above), of which specific examples are the following compounds.
These compounds can be prepared by a conventional or known technique.
[7-1] 1-(meth)acryloyloxyadamantane (R1xe2x95x90H or CH3, R23xe2x95x90H); and
[7-2] 1- (meth)acryloyloxy-3,5-dimethyladamantane (R1xe2x95x90H or CH3, R23xe2x95x90CH3).
[Monomer Unit of Formula (VIII)]
Monomers constituting the monomer units of Formula (VIII) are represented by the following Formula (8): 
(wherein R1, R24 and R25 have the same meanings as defined above),
of which typical examples include the following compounds.
These compounds can be obtained by a known or conventional process such as a process in which a corresponding alcohol (HOxe2x80x94R24xe2x80x94R25) and (meth)acrylic acid or its derivative (14) are subjected to an esterification reaction.
[8-1] 8-hydroxymethyl-4-(meth)acryloyloxymethyltricyclo[5.2.1.02,6]decane;
[8-2] 4-hydroxymethyl-8-(meth)acryloyloxymethyltricyclo[5.2.1.02,6]decane;
[8-3] 4-(meth)acryloyloxymethyltetracyclo[4.4.0.12,5.17,10]dodecane;
[8-4] 2-(meth)acryloyloxynorbornane;
[8-5] 2-(meth)acryloyloxyisobornane; and
[8-6] 2-(meth)acryloyloxymethylnorbornane. 
[Monomer Unit of Formula (IX)]
Monomers constituting the monomer units of Formula (IX) are represented by the following Formula (9): 
(wherein R1, R27, R28, R29, R30 and R31 have the same meanings as defined above),
of which typical examples include the following compounds:
[9-1] 2-(meth)acryloyloxy-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90R28xe2x95x90R29xe2x95x90R30xe2x95x90R31xe2x95x90H);
[9-2] 2-(meth)acryloyloxy-2-methyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90CH3, R28xe2x95x90R29xe2x95x90R30xe2x95x90R31xe2x95x90H);
[9-3] 2-(meth)acryloyloxy-4,4-dimethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90R28xe2x95x90R29xe2x95x90H, R30xe2x95x90R31xe2x95x90CH3);
[9-4] 2-(meth)acryloyloxy-2,4,4-trimethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90R30xe2x95x90R31xe2x95x90CH3, R28xe2x95x90R29xe2x95x90H);
[9-5] 2-(meth)acryloyloxy-3,4,4-trimethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90R29xe2x95x90H, R28xe2x95x90R30xe2x95x90R31xe2x95x90CH3);
[9-6] 2-(meth)acryloyloxy-2,3,4,4-tetramethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90R28xe2x95x90R30xe2x95x90R31xe2x95x90CH3, R29xe2x95x90H);
[9-7] 2-(meth)acryloyloxy-3,3,4-trimethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90R31xe2x95x90H, R28xe2x95x90R29xe2x95x90R30xe2x95x90CH3);
[9-8] 2-(meth)acryloyloxy-2,3,3,4-tetramethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90R28xe2x95x90R29xe2x95x90R30xe2x95x90CH3, R31xe2x95x90H);
[9-9] 2-(meth)acryloyloxy-3,3,4,4-tetramethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90H, R28xe2x95x90R29xe2x95x90R30xe2x95x90R31xe2x95x90CH3); and
[9-10] 2-(meth)acryloyloxy-2,3,3,4,4-pentamethyl-xcex3-butyrolactone (R1xe2x95x90H or CH3, R27xe2x95x90R28xe2x95x90R29xe2x95x90R30xe2x95x90R31xe2x95x90CH3).
The compounds represented by Formula (9) can be obtained, for example, pursuantly to the following reaction process chart: 
(wherein Rz is a hydrocarbon group; and R1, R27, R28, R29, R30, R31 and Rx have the same meanings as defined above).
The hydrocarbon group in Rz in the above reaction process chart includes, for example, methyl, ethyl, propyl, s-butyl, t-butyl, vinyl, allyl and other aliphatic hydrocarbon groups (alkyl groups, alkenyl groups or alkynyl groups) each having from about 1 to about 6 carbon atoms; phenyl group, naphthyl group and other aromatic hydrocarbon groups; and cycloalkyl groups and other alicyclic hydrocarbon groups.
A reaction of xcex1,xcex2-unsaturated carboxylic ester (30) with alcohol (31) and oxygen is performed in the presence of a N-hydroxyimide catalyst such as N-hydroxyphthalimide, and where necessary, a metallic promoter such as a cobalt compound (e.g., cobalt acetate or acetylacetonatocobalt). The ratio of xcex1,xcex2-unsaturated carboxylic ester (30) to alcohol (31) can be appropriately selected depending on the types (e.g., cost and reactivity) of the two compounds. For example, alcohol (31) may be used in excess (e.g., about 2 to 50 times by mole) to xcex1,xcex2-unsaturated carboxylic ester (30), and vice versa, xcex1,xcex2-unsaturated carboxylic ester (30) may be used in excess to alcohol (31). The amount of the N-hydroxyimide catalyst is, for example, from about 0.0001 to about 1 mole and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the compound which is used in a less amount between xcex1,xcex2-unsaturated carboxylic ester (30) and alcohol (31). The amount of metallic promoter is, for example, from about 0.0001 to about 0.7 mole and preferably from about 0.001 to about 0.5 mole, relative to 1 mole of the compound which is used in a less amount between xcex1,xcex2-unsaturated carboxylic ester (30) and alcohol (31). Oxygen is often used in excess to the compound which is used in a less amount among xcex1,xcex2-unsaturated carboxylic ester (30) and alcohol (31). The reaction is performed in a solvent at a temperature of from about 0xc2x0 C. to about 150xc2x0 C. and preferably from about 30xc2x0 C. to about 100xc2x0 C. at atmospheric pressure or under a pressure (under a load). Such solvents include, but are not limited to, acetic acid and other organic acids, acetonitrile and other nitrites, trifluoromethylbenzene and other halogenated hydrocarbons, and ethyl acetate and other esters.
A reaction between thus obtained xcex1-hydroxy-xcex3-butyrolactone derivative (32) and (meth)acrylic acid or its derivative (14) can be carried out pursuantly to the reaction between 1-adamantanol derivative (13) and (meth)acrylic acid or its derivative (14).
[Monomer Unit of Formula (X)]
Monomers constituting the monomer units of Formula (X) are represented by the following Formula (10): 
(wherein R1 and n have the same meanings as defined above), of which typical examples include the following compounds:
[10-1] 2-tetrahydropyranyl (meth)acrylate (R1xe2x95x90H or CH3, n=2); and
[10-2] 2-tetrahydrofuranyl (meth)acrylate (R1xe2x95x90H or CH3, n=1).
[Monomer Unit of Formula (XI)]
Monomers constituting the monomer units of Formula (XI) are represented by the following Formula (11): 
(wherein R1 has the same meaning as defined above), of which specific examples are the following compounds:
[11-1] (meth)acrylic acid (R1xe2x95x90H or CH3).
The invented polymeric compounds have all of transparency, alkali-solubility, adhesion and etching resistance as described above, and can be advantageously used as photoresist resins.
A photoresist resin composition of the present invention comprises the invented polymeric compound and a light-activatable acid generator.
As the light-activatable acid generator, known or conventional compounds that can efficiently generate an acid by action of exposure can be employed. Such compounds include, but are not limited to, diazonium salts, iodonium salts (e.g., diphenyliodonium hexafluorophosphate), sulfonium salts (e.g., triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, and triphenylsulfonium methanesulfonate), sulfonates [e.g., 1-phenyl-1-(4-methylphenyl)sulfonyloxy-1-benzoylmethane, 1,2,3-trisulfonyloxymethylbenzene, 1,3-dinitro-2-(4-phenylsulfonyloxymethyl)benzene, and 1-phenyl-1-(4-methylphenylsulfonyloxymethyl)-1-hydroxy-1-b enzoylmethane], oxathiazol derivatives, s-triazine derivatives, disulfone derivatives (e.g., diphenyldisulfone), imide compounds, oxime sulfonates, diazonaphthoquinone, and benzoin tosylate. Each of these light-activatable acid generators can be used alone or in combination.
The amount of the light-activatable acid generator can be appropriately selected depending on the strength of an acid generated by light irradiation or the proportion of each monomer unit in the polymeric compound, and is, for example, from about 0.1 to about 30 parts by weight, preferably from about 1 to about 25 parts by weight, and more preferably from about 2 to about 20 parts by weight, relative to 100 parts by weight of the polymeric compound.
The photoresist resin composition may further comprise additional components. Such additional components include, but are not limited to, alkali-soluble resins (e.g., novolak resins, phenol resins, imide resins, and carboxyl-group-containing resins), and other alkali-soluble components, coloring agents (e.g., dyestuffs), and organic solvents (e.g., hydrocarbons, halogenated hydrocarbons, alcohols, esters, amides, ketones, ethers, Cellosolves, Carbitols, glycol ether esters, and mixtures of these solvents).
The photoresist resin composition is applied onto a base or a substrate and is dried, and the resulting film (resist film) is exposed to light through a -predetermined mask (or is further subjected to post-exposure baking) to form a latent image pattern, and the film is then developed to thereby highly precisely yield a fine pattern.
Such bases or substrates include, for example, silicon wafers, metals, plastics, glasses and ceramics. The photoresist resin composition can be applied using a conventional application means such as a spin coater, a dip coater and a roller coater. The applied film has a thickness of, for example, from about 0.1 to about 20 xcexcm, and preferably from about 0.3 to about 2 xcexcm.
Light rays with different wavelengths, such as ultraviolet rays and X-rays, can be used for exposure. For example, g-ray, i-ray, and excimer laser (e.g., XeCl, KrF, KrCl, ArF, or ArCl) are usually used for semiconductor resists. An exposure energy is, for example, form about 1 to about 1000 mJ/cm2, and preferably from about 10 to about 500 mJ/cm2.
An acid is generated from the light-activatable acid generator by action of light irradiation, and the acid immediately eliminates the protective group (leaving group) of the carboxyl group of the polymeric compound. Thus, a carboxyl group that contributes to solubilized resin is formed. Subsequent development with water or an alkali developer can precisely form a predetermined pattern.
According to the present invention, the polymer includes a monomer unit having an adamantane skeleton of a specific structure and can exhibit high etching resistance in addition to satisfactory transparency, alkali-solubility and adhesion. Accordingly, the invented polymeric compound is useful as a photoresist resin for use in, for example, the micromachining of semiconductors.